1. Technical Field
This invention relates generally to shaft seals and more particularly to such seals having debris-excluding features.
2. Related Prior Art
Dynamic shaft seals are used in many automotive, machine, heavy equipment, construction, agricultural, industrial applications, etc., for sealing the opening in a case or housing through which a rotating shaft extends. The seal functions to contain a lubricant such as oil on one side of the seal and to exclude contaminants on the opposite atmosphere or air side of the seal.
Numerous prior seals are known wherein a primary lubricant-retention lip is used in combination with a plurality of debris-excluding features which may take the form of shaft-engaging lips, elastomeric excluders, labyrinth passages, and porous filter elements. The present invention provides a particular combination and arrangement of dust excluding features that cooperate with one another to protect the primary lubricant-retention seal from contaminants while permitting each feature to perform its debris-excluding task in an efficient manner.